This invention relates to a fuel injection system for an internal combustion engine, and more particularly, the invention relates to an integrated fuel rail, fuel injector, and injector wires.
Modern internal combustion engines typically use fuel injectors to increase fuel efficiency and control over engine operation. Commonly, a fuel injector is used for each engine cylinder. The fuel injectors receive fuel from a fuel rail and are supported in an intake manifold. A valve in the injector meters fuel from the fuel rail into the engine cylinder at a desired time during the engine cycle.
A fuel injection system typically includes many components that must be assembled, which increases the likelihood of fuel permeating or leaking from the system. The fuel injectors may include an O-ring or seal at opposing ends that are received in the fuel rail and intake manifold. For a six-cylinder engine, up to twelve seals may be needed for the fuel injection system. Presently, there are very strict rules limiting the amount of hydrocarbons that may permeate from a vehicle. Each connection between components presents a potential for permeation of fuel in gaseous form. Furthermore, the fuel injection system is under relatively high pressures. As a result, there is an increased opportunity for fuel to leak past the seals. Therefore, what is needed is a fuel injection system that reduces the number of components and assembly required while improving the resistance to fuel permeation or leakage from the system.
The present invention provides a fuel injection system for an internal combustion engine that includes a fuel injector having an injector housing with first and second opposing portions. An injector passage extends between the first and second portions. A valve is disposed in the injector passage for selectively permitting fuel to flow from the first portion to the second portion. A fuel rail having a fuel passage includes a first opening receiving the first portion with the injector passage and fluid communication with the fuel passage. An intake manifold has a second opening receiving the second portion. A polymer layer extends from the fuel rail and intake manifold about at least a portion of the fuel injector sealing the first and second portions respectively to the fuel rail and intake manifold for preventing fuel from leaking from the fuel injection system. In this manner, an integrated intake manifold fuel rail and fuel injector may be provided that eliminates the numerous seals typically used and reduces the potential for fuel leakage.
The polymer layer may also form the fuel rail and intake manifold such that a separate fuel rail and intake manifold is not required. Alternatively, the polymer layer may form the fuel rail only and the fuel rail may be connected to the intake manifold thereby eliminating half of the seals typically required.
The injector wiring may also be integrated into the fuel injection system. The fuel rail may include a cavity for receiving wires that are connected to electrical contacts extending from the injectors into the cavity. A plastic material may be molded into the cavity to enclose the wires from the outside environment.
Accordingly, the above invention provides a fuel injection system reducing the number of components and assembly associated with construction of the fuel injection system while reducing the potential for fuel leakage.